Litho-grain printing-plate.



F. NEEMEYER. LiTHO-GRAIN PRINTING PLATE.v

APPLICATION FILED AUG.22. I912.

Pamnted Dec. 7, 1915.

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FREDERICK NIEMEYER, F HOBOKEN, NEW JERSEY.

LITI-IO-GRAIN PRINTING-PLATE.

Specification of Letters Patent.

Application filed August 22, 1912. Serial No. 716,438.

To all whom it may concern:

Be it known that I, FREDERICK NIEMEYER, a citizen of the United States, residing in Hoboken, in the county of Hudson and 6 State of New Jersey, have invented certain new and useful Improvements in Litho- Grain Printing-Plates, of which the following is a specification.

This invention relates to surface-grained metal plates for use in printing by the lithographic method, and relates more particularly to litho-grain zinc plates for such uses.

A principal object of my present improvements is to furnish a metallic printingplate, and particularly a zinc litho-grain printing-plate which shall have a grain-surface modified by an association in and with the surface-atoms thereof, of atoms of a different metal which is of a kind having the quality of making or forming an alloyunion with zinc, and so form or produce a surface-structure or grain of an undulatory character and more resistant to the impairment by atmospheric and other agencies, While retaining the other required qualities. For thispurpose, in the making of the plate, I preferably employ granules of a metal or metals, or of a salt or composition having a modifier-metal as a component thereof, and while these modifier-granules are deposited or depositing on the plate-surface 1n an acid bath, I subject both the said salt or granules and the plate surface while thus in intimate contact, simultaneous reduction by the acid, and preferably to successive such reductions.

A. process for litho-graining metal plates and adapted for producing the hereindescribed litho-grain zinc printing-plates, forms the subject-matter of my concurrently pending application, Serial No. 67 9,745, filed Feb. 24:, 1912, and allowed May 4, 1912. A further improvement in processes for making such plates is set forth and claimed. in my other application, Serial No. 716,439, filed Aug. 22, 1912, and concurrently pending herewith. And such other features-of improvement in those processes and in the plates as produced thereby, as are set forth but are not claimed herein, will form in part the subject-matter of other applications to be filed by me, and to be concurrently pending herewith.

In the accompanying drawing forming a part of this specification,Figure 1 is an enlarged and diagrammatic perspective view lllustrative of a fragment of a litho-grain printing plate made in accordance with my present improvements. Fig. 2 is a sectional v1ev\ on a greatly enlarged scale for illustratlng 1n a dlagrammatic manner, certain features hereinafter more fully explained.

Similar reference characters designate like parts in all the views.

For making my improved litho-grain plate, I prefer to follow in a general Way a method substantially such as described in my aforesaid application, Serial N 0. 679,7 15. One feature of that process, relates to the employment of granules having therein a metal other than the metal of the plate, and other features relate to the way such granules may be employed or utilized, as

therein more fully set forth. In making the plates according to my present invention, the metal of the granules, (or one such metal in cases where a plurality of metals are contained in the granules) is preferably one which readily alloys withthe metal of the plate, and in varying proportions. Of such metals, zinc is well adapted for the plate, While copper is suitable as a metal for use in the granules, and these two metals combine or directly associate together to form a metal different from either one alone, and I have discovered that some of these compositions are particularly suitable for the grain-surfaces of metal lithographic printing plates.

In Fig. 1, the plate as a whole is designated by I, and the grain upon or forming its upper surface being indicated by n. The plate P is here shown of much greater thickness than is necessaryin practice, while the grain n is only represented in a diagrammatic manner, Whichis further illustrated at n, F1g.- 2, here. the plate P is greatly enlarged in thlckness. The line 3, Fig. 2, gives approximately the height of the original upper surface of the blank plate, so that the unshaded space at 1, below the line 3 and above the undulating line 55, indicates how the metal of the blank plate is dissolved away during the process of making thereon the lithe-grain.

Below the grain-surface line 55, I have drawn the line 6 (also indicated in Fig. 1) parallel to the line 3, for indicating substantially the lower boundary of the grain- Patented Dec. 7, 1915. v

formation, so that the metal above the line 6 and below the line 5-5,- may be said to form the body of the grain formation, except that the metal in a narrow sectional zone, as e, lying between the correspondingly .undulating lines 55 and 77, may be said to constitute the surfaceformation, or the surface-zone of the grain-formation.

In Fig. 2, the sectional area is indicated by the short, inclined dashes, as at d, and these in the case of a zinc plate may be assumed to diagrammatically represent the atoms of zinc. In the narrow surface zone 6, however, round dots are interspersed with the dashes for similarly illustrating a modified surface-formation in said zone 6 by .means of an increment of another metal,

(such, for instance, as copper when the plate body is zinc), the atoms of which are directly associated by incorporation among the zinc atoms. In the case of zinc having copper thus associated in the surface-formation of the grain, and when, as above described, that union or association is of an alloy nature, the resultant modification will evidently have, or tend toward, the character 'of brass, thereby furnishing a bright and peculiarly resistant and desirable surface for use in this art. A litho-grain having its surface formation thus modified (or, so to speak, brassified), takes and retains the substance of the artists crayon with peculiar facility, and also readily receives and properly retains the necessary amount of water or moisture while the plate is in use.

When copper is associated with cyanogen (as in a cyanate, for instance) in minute granules which are in contact with zinc and are there subjected to dissociation in a suitably dilute nitric acid bath, it appears that while the copper-granule is attacked by one agent, (the nitric acid), the zinc is attacked by both the acid and the cyanogen; and, also, it appears probable, as I now apprehend, that this attacking cyanogen in leaving the copper to join and help dissolve the zinc, may tend to carry some copper atoms into union with zinc atoms not then fully dissolved or displaced, but only incipiently so, and thus bring about a direct association of some copper atoms with suflicient zinc atoms for effecting the desired protective modification of the undulatory grain-surface. The chemical-action, and re-actions which occur during the process may, as I now deem probable. include such as are designatedas a ring, particularly when the granules are a double-salt. Thus, as I now apprehend, the relatively nascent atoms of the zinc and of the said other metal, in part unite in the surface of the plate, in some vmanner which, (though'not yet fully known) appears be analogous to alloying. In practice this surface may be of a relatively small depth, and yet be a solid metal surface free of any coating, and having this metal surface of the nature of an intermixture or alloy, as distinguished from the merely deposited coatings heretofore known in this art. By using granules having a copper content, the resultant modification of the plate surface may be or have the nature of brass, but of a low proportion of copper, giving the desired silvery whiteness, and also a suitable quality and resistance. The said granule or modifier substance is thus subjected to a dissociative action while in contact with,and concurrently with the dissolving away of, those zinc atoms which are removed to form the grain-structure, so that the resultant modified surface is not only grained and brought into a roughened and undulatory shape or form, but the modified part of surface (consisting of the modified-metal), normally follows. over and conforms to those undulatory surfaces or forms, and thus gives to the plate a distinct and improved character.

If in the operation of making the lithograin on a zinc plate with the aid of granules yielding copper, there should be some deposition of copper 011 the grain-surface at the time the grain has reached the desired depth, or size and character, such deposition or coating may be readily and quickly removed by cleaning the plate, preferably at the end of the grain-forming stage of the operation, with a dilute muriatic acid wash, thus removing any extraneous materials and coatings, and leaving the modified surfaceformation of the litho-grain in a clean, brightand unimpaired condition.

In some instances the modifier-substance,

when applied to the blank plate for concurrent reduction therewith, may comprise a plurality of metals each different from the metal of the plate, such, for instance, as copper and iron, (when the plate is not of copper or iron), and these modifier-metals may be supplied in granules consisting in part or wholly of some suitable double-salt, and particularly a double-cyanate. Thus the modifier-metal may be a plurality of metals each of which (or the plurality taken together) are adapted to form an alloyunion with the surface atoms of the plate; but this three-metal surface-formation is a feature I do not specifically claim herein, but reserve the same to form the subjectmatter of a separate application to be filed therefor.

One advantage obtained in using my im proved litho-grain on zinc plates is the avoidance, after the picture has been transferred thereto, of the picking up of flakes and other dbris by the inking roller when the workman proceeds to roll up the plates. A further advantage is that a minimum quantity of water may be used, and this may be applied by a less moist roller,

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since the modified metal surface of a zinc plate holds the moisture with extreme evenness, and thus favors the printing operations, especially when running on highclass Work.

When the plate is grained as set forth herein by description and reference to my said prior application, No. 679,745, (since issued as Letters Patent No. 1045068, dated Nov. 19, 1912) it Will be seen that the grain-formation is located below'the original surface, 3, of the plate P, and is produced by a mass-reduction of the plate; and that the grain-formation is metal-surfaced and has no supplemental layer or coating materials applied thereon, but has the grain-surface modified by an incorporated increment not in the nature of a layer, nor applied subsequently to the completion of the plate-reduction. In this improved plate, the undulatory grainforms,such for instance as at n, Fig. 2,-, are composed of the undisplaced surface atoms of the metal of the reduced plate, and by reason of the manner, as set forth, of such plate-reduction by the granule-regulation of the acld-reduction operation, these grain-form outlines join together to make an extended undulatory plate-surface having a metal-surfaced and capillary quality,

and free of adherent coatings and of sharp or harsh points or edges.

Having thus described my invention, I claim:

l. A zinc printing-plate for lithographic printing, having one of its surfaces acidetched into an undulated surface, and modified by copper to form an alloy with the zinc of the plate, the copper having alloyed with the zinc included in said etched surface during the etching process.

2. A metallic printingplate for litho-' graphic printing, having one of its surfaces acid-etched into an undulated surface, and such undulated surface modified by a second metal to an extent less than the formation of a superimposed coating thereby to form a surface composed of an alloy With the metal of the plate.

8. A printing plate having one side there of litho-grained over the entire printingarea thereof, and having said litho-grain of a finely-undulated surface consisting of the metal of the plate, having incorporated therein a surface-modifying metallic increment of particles in a non-layer form.

FREDERICK N IEMEYER.

Witnesses:

H. DVPENNEY, JOHN Momus.

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